perl: Binding and test for guestfs_last_errno (RHBZ#672491).

generator/generator_perl.ml

@@ -262,6 +262,17 @@ PREINIT:
 
       guestfs_delete_event_callback (g, event_handle);
 
+SV *
+last_errno (g)
+      guestfs_h *g;
+PREINIT:
+      int errnum;
+   CODE:
+      errnum = guestfs_last_errno (g);
+      RETVAL = newSViv (errnum);
+ OUTPUT:
+      RETVAL
+
 ";
 
   List.iter (
@@ -625,6 +636,9 @@ with libvirt.
 
 All errors turn into calls to C<croak> (see L<Carp(3)>).
 
+The error string from libguestfs is directly available from
+C<$@>.  Use the C<last_errno> method if you want to get the errno.
+
 =head1 METHODS
 
 =over 4
@@ -738,6 +752,26 @@ this function.
 This removes the callback which was previously registered using
 C<set_event_callback>.
 
+=item $errnum = $h->last_errno ();
+
+This returns the last error number (errno) that happened on the
+handle C<$h>.
+
+If successful, an errno integer not equal to zero is returned.
+
+If no error number is available, this returns 0.
+See L<guestfs(3)/guestfs_last_errno> for more details of why
+this can happen.
+
+You can use the standard Perl module L<Errno(3)> to compare
+the numeric error returned from this call with symbolic
+errnos:
+
+ $h->mkdir (\"/foo\");
+ if ($h->last_errno() == Errno::EEXIST()) {
+   # mkdir failed because the directory exists already.
+ }
+
 =cut
 
 ";

perl/t/810-mkdir-eexist.t

@@ -0,0 +1,76 @@
+# libguestfs Perl bindings -*- perl -*-
+# Copyright (C) 2011 Red Hat Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+# Test $g->last_errno (RHBZ#672491).
+
+use strict;
+use warnings;
+use Test::More tests => 15;
+
+use Errno;
+
+use Sys::Guestfs;
+
+my $g = Sys::Guestfs->new ();
+ok ($g);
+
+open FILE, ">test.img";
+truncate FILE, 500*1024*1024;
+close FILE;
+ok (1);
+
+$g->add_drive_opts ("test.img", format => "raw");
+ok (1);
+
+$g->launch ();
+ok (1);
+
+$g->part_disk ("/dev/sda", "mbr");
+ok (1);
+$g->mkfs ("ext2", "/dev/sda1");
+ok (1);
+
+$g->mount_options ("", "/dev/sda1", "/");
+ok (1);
+
+# Directory doesn't exist, so this mkdir should succeed.
+$g->mkdir ("/foo");
+ok (1);
+
+# Directory exists, we should be able to recover gracefully.
+eval {
+    $g->mkdir ("/foo");
+};
+ok ($@);
+my $err = $g->last_errno ();
+ok ($err > 0);
+ok ($err == Errno::EEXIST());
+
+# Can't create subdirectories with missing parents; this should
+# be a different errno.
+eval {
+    $g->mkdir ("/bar/baz");
+};
+ok ($@);
+$err = $g->last_errno ();
+ok ($err > 0);
+ok ($err != Errno::EEXIST());
+
+undef $g;
+ok (1);
+
+unlink ("test.img");